[Evolution] preferred language

[Xavier Bestel <n0made free fr>]

Hi !

There should be an entry in the contact list for the "preferred language": this
would enable an application which would access the contact list to retrieve an
email address to send automatically the email in the right language.
Explanation: I have in mind an application which should automatically send a
mail to some of your contacts, and being able to know which language to use is a
definite plus. So there should be a hook te retrieve this.

        Xav